2.1.2 provoke TypeError: Cannot read property 'length' of undefined in es6-promise

[cyrilgandon]

I create an issue in Karma, but my guess is it is more relevant here.
Karma related issue : karma-runner/karma#1946
es6-promise related issue : stefanpenner/es6-promise#169

Stack trace:

TypeError: Cannot read property 'length' of undefined
    at lib$es6$promise$$internal$$fulfill (.\node_modules\grunt-ts\node_modules\csproj2ts\node_modules\es6-promise\dist\es6-promise.js:273:31)
    at lib$es6$promise$$internal$$resolve (.\node_modules\grunt-ts\node_modules\csproj2ts\node_modules\es6-promise\dist\es6-promise.js:255:9)
    at lib$es6$promise$$internal$$invokeCallback (.\node_modules\grunt-ts\node_modules\csproj2ts\node_modules\es6-promise\dist\es6-promise.js:366:9)
    at .\node_modules\grunt-ts\node_modules\csproj2ts\node_modules\es6-promise\dist\es6-promise.js:891:13    
    at lib$es6$promise$asap$$flush (.\node_modules\grunt-ts\node_modules\csproj2ts\node_modules\es6-promise\dist\es6-promise.js:125:9)    
    at doNTCallback0 (node.js:408:9)
    at process._tickCallback (node.js:337:13)

This commit should have provoke the regression : 3b8292d#diff-ee864bf9a84ab105426dbe4fbbad2a69

But my knowledge of node.js is close to zero, so it's just a guess.

The stacktrace seems to lead to this particular line:
https://github.com/stefanpenner/es6-promise/blob/master/lib/es6-promise/-internal.js#L127

As both es6-promise and core-js depend on nothing, I bet that error occured when both are called from other libraries, like in my case, grunt-ts(depends on es6-promise) and karma(depends on core-js).

I also bet that one overwrites global stuff from the other, which explains why error occured when both are called from the same process, and not when they are called one task after the other on different process.

[thomastardy]

Facing the same issue

[oliversommer]

for me it's related to core-js which is a transitive dependency of karma. I pinned core-js at 2.1.1 and this way it works for me. at least a quick fix.

[zloirock]

It's a bug in es6-promise. In feature detection, core-js detected @@species constructor pattern support in Promise#then. es6-promise not supports it and throws an error. Feature detection wrapped in try / catch, but an error throws async.

[zloirock]

Reproducible example:

require('es6-promise');
var p = Promise.resolve();
p.constructor = function(it){ it(function(){}, function(){})};
p.constructor[Symbol.species] = function(it){ it(function(){}, function(){})};

try {
  var f = p.then(function(){});
  console.log('works: ', f instanceof p.constructor[Symbol.species]);
} catch(e){
  console.log('caught error');
}

[zloirock]

I will add a fallback for this buggy implementation, need to think how.

[zloirock]

In 2.1.3 added a fallback for this es6-promise bug.

[cyrilgandon]

Thank you @zloirock for your hard work! 👍

[stefanpenner]

Es6-promise should also no longer cause this crash